An information sharing system including a plurality of on-vehicle diagnosis terminals and one or more of display terminals sharing diagnostic information over wireless communication. The respective terminals store, in a storing unit, data sets, also stored in another terminal with which communication was established, and a stored clock time. The terminals include a communication-establishing unit that includes a searching unit and an establishing unit. The searching unit is configured to search an planned-connection terminal capable of establishing communication with the terminal, and that does not yet have a stored clock time, or the stored clock time that is stored in the on-vehicle diagnosis terminal and from which a predetermined time has passed, and the establishing unit is configured to establish communication with the planned-connection terminal.